Oil Pressure Help

[Synestran]

Going to check to see if I put the wrong bolt in the head tomorrow. If nothing else, going to remove the engine so I can get a good look at the gallery plugs. There is no oil leaking out the back but maybe missing the front one?

[datzenmike]

Maybe. Running out of possibilities.

[Synestran]

Looked at the head and the bolt is longer but thinner than the others and the only one that seems to properly fit in the passenger side middle of the head.

Took the timing cover off and I can just barely see what appears to be about a nickel sized plug of some sort behind one of the gears.

So I'm not sure what to do at this point.

Oh, and that waisted bolt didn't say 12t on it, it says 13 but the top of the bolt is different than the others too.

[Tom1200]

First on the bolts the middle passenger side is correct; the 13 is the newer higher torque bolt. It should be about 15mm longer and 7.8mm thick versus 8.8 for,the rest of the bolts.

 

Next we are actually getting somewhere as you have eliminated two of the issues. The head bolt and that oil plug that nickel size plug you see behind the cam gear is the oil gallery plug. Before you pull the motor I would try two things; if you haven't you really really need to pull the pump and see if you can suction oil up out of the pickup. Either the port in the block is obstructed or the tube. After you establish that oil can be sucked out of the pan next pressurize the block. You should be able to pump oil into the top end with not a lot of pressure. I'm still leaning towards the some kind of pick up issue.

 

Tom

[Stoffregen Motorsports]

You could try a new oil pump.

 

Did you get a new one when the engine was rebuilt? Maybe it's faulty.

 

Did someone rebuild the old pump? Maybe they screwed up.

[datzenmike]

He put the old one back in and tried it... same results.

[bilzbobaggins]

What drives the oil pump on an a series motor?

[wayno]

I have never rebuilt an A series engine before, so I don't know how the oil pump is turned/driven.

I have a U20 in my Datsun Roadster, I bought this engine rebuilt 20 years prior, I took it to my machine shop to have a cylinder sleeve put into one cylinder because water had gotten into the cylinder at some point in the 20 years it had sat and rust pitted it, there was this sleeve that dropped into the distributor shaft hole that was forgotten by the prior owner and was never installed, it was sort of pressed in but was removed when the engine block was cleaned before the rebuild, well without this distributor sleeve in place, the oil was just pumped up into the area the sleeve was supposed to be and it just fell back into the oil pan because the sleeve wasn't there, it did pump enough oil to pump it out of a forgotten oil sensor hole, but I have no idea if the oil filter ever filled, I do know that the top of the engine never seen any oil, and when the assembly lube was gone, the cam started squeaking and I shut it down, the cam hole needed a little attention, and so did one of the rod bearings, otherwise the engine survived and runs great to this day.

Is there such a sleeve in the A series engine that can be left out when the block is cleaned and rebuilt?

Is there another shaft being driven by the cam that could have been left out therefore the oil pump never has turned?

[Stoffregen Motorsports]

There are two different A series cams and they have different distributor drive locations. I wonder if the oil pump drive location is the same. Did you replace the cam?

 

Boy, at this point, I would say it's time to pull it out and take of the oil pan and front cover, check the oil pickup for cracks and bends, make sure all the galley plugs and cam bearings are in there...

 

You know, if the machine shop boiled the block, they probably removed the cam bearings. Did you put new ones in or have them put new ones in? Lack of cam bearings would certainly cause a no-oil-pressure situation.

[Synestran]

The oil pump is working as it has oil coming out if I remove the oil filter.

The guy I took the engine to replaced the can bearings as the other ones were getting worn down. It's not a new can shaft but one I sent out to add a little performance to.

When the head bolt was out, I was able to pour some oil in the hole and it was draining so it doesn't appear to have some sort of blockage in it.

How much oil should be coming out the holes on the rocker arm?

Oh, I also blew some air down the head bolt hole and could hear the air circulating as well.

[Tom1200]

I had to check the oil path diagram to try and come up next steps:

 

What changed; you mentioned cam bearings, I've only ever had one set replaced one set and can't think of how an install would cause lack of pressure. The oil goes from the crank to the cam bearings and so if the oil passage where some how blocked you should still have oil pressure. Perhaps if they were reamed out to far? I'll have to look through manual some more.

 

As for how much oil comes out the rockers; can't quantifably answer that one but given that it would have 25-60psi I would say a good bit. As there is no oil going into the top end we have to presume the problem is between the pump output and the passage to the top end.

 

Tom

[wayno]

I would ask this question after reading this thread again, how fast did the oil come out when you started it without the oil filter on it?

You said it came out at a steady flow, did it come out fast enough to empty the oil pan quickly(like water faucet turned on full), or did it come out like a water faucet only turned on a little ways? 

[Stoffregen Motorsports]

Yeah, the cam bearings are suspect in my book. They do have grooves in them. They also have multiple oiling holes in them that need to be clocked appropriately or the holes in the bearing won't match up with the holes in the block. Diagnosing this may require the engine to be partially disassembled. Ask your friend who put the cam bearings in if he noticed multiple holes or singular holes.

 

Some cams are ground with different grooves too.

 

I don't have an oiling diagram either, so this is all speculation. It's been a few years since I built an A-series.

[Synestran]

I would ask this question after reading this thread again, how fast did the oil come out when you started it without the oil filter on it?

You said it came out at a steady flow, did it come out fast enough to empty the oil pan quickly(like water faucet turned on full), or did it come out like a water faucet only turned on a little ways? 

It seemed to come out like a faucet turned on all the way. It was a good amount.

 

Yeah, the cam bearings are suspect in my book. They do have grooves in them. They also have multiple oiling holes in them that need to be clocked appropriately or the holes in the bearing won't match up with the holes in the block. Diagnosing this may require the engine to be partially disassembled. Ask your friend who put the cam bearings in if he noticed multiple holes or singular holes.

 

Some cams are ground with different grooves too.

 

I don't have an oiling diagram either, so this is all speculation. It's been a few years since I built an A-series.

 

I remember seeing the grooves in the cam bearings and aligning the holes up to where they are supposed to be at. 

I have the engine out at the moment and going to go through it to check to make sure nothing is out of place.

[Stoffregen Motorsports]

If there is a lot of oil shooting out, and the pressure is low, there has to be a blockage somewhere. If there was no oil flowing, that would be a different story.

 

I found these charts on datsun1200.com

 

 

 

It looks like (and if I recall correctly) the oil to the cylinder head flows through the cam bearings. I also remember having a similar problem in the past with the grooves in the cam not being ground properly. If the oiling groove is not present in the cam, oil cannot pass. You said you had your cam reground, right? Are you sure they didn't take your cam and give you another one? At this point, you might consider getting your hands on a stock A cam and comparing the oil grooves to the cam that's in the motor.

[Synestran]

Hey guys, while the engine was out I checked the bearings and those were good. Blew some more air and everything seemed clear as far as blockages. Put it back in and now have oil everywhere it's supposed to be.

Thanks to everyone for helping me figure out how the oil system works and helping me troubleshoot the problem.

[racerx]

so what happened?

[wayno]

I hate when that happens, I want to know why it happened, that way it don't happen again.

[racerx]

Exactly Wayno...it's like watching a good movie and the power cuts off and your dying to know what happened

[Stoffregen Motorsports]

I don't buy it. Some piece of the puzzle is missing.

 

So the engine has oil flow and oil pressure reading on the gauge? and you found nothing during the inspection?

[Synestran]

I don't think the gauge was working to begin with so when I had it hooked up, nothing was reading. I didn't have anything else to try it on so I couldn't verify it was working or not.

I'm not really sure why it started working. I had the engine out and was upside down for about 2 days on the engine stand. After checking the bearings and putting everything back together and checking to make sure there were no blockages I put the engine back in. I was blowing air through the passages so I'm thinking that something was plugged and came free. I'm also thinking the other part of the problem from the beginning was that the oil pickup tube wasnt on properly and was sucking air through the gasket. I didn't run it very long before taking the engine out as I was afraid of hurting something if no oil was getting to the top end so my mechanic friend came over and was thinking I wasn't running it long enough for the initial oil to get all the way to the top of the engine. So, not entirely sure what changed but it is now lubricating as it should.

[banzai510(hainz)]

I would have pulled the oil filter and see if it shot out while cranking.  Gauge or no gauge.  15 sec ck.

 

should have pressure in like 15secs if primed.

[Tom1200]

I'd bet $2 (double my normal amount) that it was the pickup tube gasket or some errant bit plugging the hole in the block between the pickup tube and pump.

[datzenmike]

I would have pulled the oil filter and see if it shot out while cranking.  Gauge or no gauge.  15 sec ck.

 

should have pressure in like 15secs if primed.

 

I'm with you Hainz, and ahead.

 

 

Post #11

Or just remove the sender. If there's oil pressure it will shoot out the hole. Maybe squirt some oil on the valve train for now.

 

 Again a week later

Did you ever take the oil filter off and run it??? This would show if oil is actually getting past the pump.

 

 

I have tried that but will try it again. It should gush out oil if it is getting oil right?

 

 

Looks like there never was a problem just a bad gauge.

[Stoffregen Motorsports]

That's my thought as well.

 

Proper diagnosis can save lots of time and money.